1. Technical Field
The present invention relates to a waste ink recovery unit, a printer, and a waste ink recovery method for recovering ink from an inkjet head into a waste ink tank.
2. Related Art
Inkjet printers are one type of fluid ejection device that ejects fluid from the nozzles of a fluid ejection head. To prevent the nozzles from becoming clogged as a result of ink in the nozzles increasing in viscosity, inkjet printers may execute a flushing operation that regularly ejects ink from the nozzles into a cap covering the nozzle face, or an ink suction operation that covers the nozzle face with a cap and forcibly removes ink from the nozzles into the cap by means of suction, for example. JP-A-2006-142630 discloses such an inkjet printer.
The inkjet printer disclosed in JP-A-2006-142630 recovers ink ejected into the cap through a tube (suction path) into a waste ink tank (waste ink recovery tank). The waste ink tank is removably installed to a tank holding unit of the inkjet printer. The waste ink tank has a box-like container and a cover, and an ink sponge made of non-woven cloth, for example, is disposed in layers inside the tank. A tube that carries the ink into the tank is attached to the back side of the cover, and the distal end of the tube extends to the middle of the tank. A channel through which the tube passes is formed in the top sponge layer. A hole in the ink sponge is formed around the inside distal end of the tube. The waste ink is thus ejected through this center hole and absorbed by the ink sponge.
Inkjet printers that eject plural different types (such as colors) of inks may have an inkjet head and a cap for each ink, and a suction path is connected to each cap. In the inkjet printer disclosed in JP-A-2006-142630, plural tubes (suction paths) lead into the waste ink tank, and the distal end openings of the tubes go to different positions. The type of colorant, and the amount of glycerin and water in the ink differs according to the type of ink, and the different inks increase in viscosity at different rates.
When the entry point (distal end opening of the tube) to the waste ink tank differs according to the type of ink as disclosed in JP-A-2006-142630, ink that easily increases in viscosity cannot easily mix with the other inks. As a result, ink that easily increases in viscosity gradually accretes, and the distal end opening of the tube may become plugged. If the distal end of the tube becomes plugged, pressure builds up in the tube as the suction pump drives. This can result in the connection disconnecting and ink leaking.